Which component is essential for a computer to connect to a network?

The Network Interface Card (NIC) is essential for a computer to connect to a network because it serves as the interface between the computer and the network itself. The NIC allows the computer to communicate with other devices on the network by converting data into a format suitable for transmission and vice versa. It can operate over wired connections, like Ethernet cables, or wireless connections, using Wi-Fi technology.

In contrast, while a hard drive stores data, and RAM temporarily holds data for quick access by the CPU, neither of these components directly facilitate network connectivity. Similarly, the monitor displays the output from the computer but has no role in connecting to a network. Hence, the NIC is the critical component required for establishing a network connection.